Directional infrasound sensing

Abstract

A method and apparatus for determining a direction of infrasound. Infrasound is received by a directional infrasound sensor comprising a plurality of channels and a plurality of sensor devices. Each channel in the plurality of channels comprises a single opening at a first end of the channel and a closed end opposite the opening. The opening of each channel in the plurality of channels is pointed in a different direction from the opening of each other channel in the plurality of channels. The plurality of sensor devices includes a sensor device at the closed end of each channel in the plurality of channels. Each sensor device in the plurality of sensor devices is configured to generate a sensor signal in response to pressure. The sensor signals generated by the plurality of sensor devices are processed to determine the direction of the infrasound received by the directional infrasound sensor.

What is claimed is: 
     
       1. A directional infrasound sensor, comprising:
 a plurality of channels, wherein each channel in the plurality of channels comprises a single opening at a first end of the channel and a closed end opposite the opening, wherein the opening of each channel in the plurality of channels is pointed in a different direction from the opening of each other channel in the plurality of channels; 
 a plurality of sensor devices comprising a sensor device at the closed end of each channel in the plurality of channels, wherein each sensor device in the plurality of sensor devices is configured to generate a sensor signal in response to pressure; and 
 a signal processing system configured to process the sensor signals generated by the plurality of sensor devices to determine a direction of infrasound received by the directional infrasound sensor. 
 
     
     
       2. The directional infrasound sensor of  claim 1 , wherein air in the plurality of channels resonates in response to infrasound received by the directional infrasound sensor. 
     
     
       3. The directional infrasound sensor of  claim 2 , wherein a shape of each channel in the plurality of channels is a fractal. 
     
     
       4. The directional infrasound sensor of  claim 1 , wherein a shape of each channel in the plurality of channels is a fractal. 
     
     
       5. The directional infrasound sensor of  claim 1 , wherein a shape of each channel in the plurality of channels along a length of the channel between the opening and the closed end of the channel is selected from straight and a coil shape. 
     
     
       6. The directional infrasound sensor of  claim 1 , wherein a length of each channel in the plurality of channels between the opening and the closed end of the channel is substantially the same as the length of each other channel in the plurality of channels. 
     
     
       7. The directional infrasound sensor of  claim 1 , wherein a length of each channel in the plurality of channels between the opening and the closed end of the channel is different from the length of each other channel in the plurality of channels. 
     
     
       8. The directional infrasound sensor of  claim 1 , wherein:
 a first opening of a first channel in the plurality of channels points in a first direction; 
 a second opening of a second channel in the plurality of channels points in a second direction, wherein the second direction is opposite to the first direction; 
 a third opening of a third channel in the plurality of channels points in a third direction, wherein the third direction is perpendicular to the first direction and to the second direction; and 
 a fourth opening of a fourth channel in the plurality of channels points in a fourth direction, wherein the fourth direction is opposite to the third direction. 
 
     
     
       9. The directional infrasound sensor of  claim 1 , wherein each channel in the plurality of channels is defined by walls made from a material selected from a group of materials consisting of concrete and metal. 
     
     
       10. The directional infrasound sensor of  claim 1 , wherein each sensor device in the plurality of sensor devices comprises a pressure sensor. 
     
     
       11. A directional infrasound sensor, comprising:
 a first directional infrasound sensor comprising a first plurality of channels, wherein each channel in the first plurality of channels comprises a single opening at a first end of the channel and a closed end opposite the opening, wherein the opening of each channel in the first plurality of channels is pointed in a different direction from the opening of each other channel in the first plurality of channels, and a first plurality of sensor devices comprising a sensor device at the closed end of each channel in the first plurality of channels, wherein each sensor device in the first plurality of sensor devices is configured to generate a sensor signal in response to pressure; and 
 a second directional infrasound sensor stacked one on top of another at a single location with the first directional infrasound sensor, wherein the second directional infrasound sensor comprises a second plurality of channels, wherein the second plurality of channels are different from the first plurality of channels, wherein each channel in the second plurality of channels comprises a single opening at a first end of the channel and a closed end opposite the opening, wherein the opening of each channel in the second plurality of channels is pointed in a different direction from the opening of each other channel in the second plurality of channels, and a second plurality of sensor devices comprising a sensor device at the closed end of each channel in the second plurality of channels, wherein each sensor device in the second plurality of sensor devices is configured to generate a sensor signal in response to pressure. 
 
     
     
       12. A method of determining a direction of infrasound, comprising:
 receiving the infrasound by a directional infrasound sensor comprising a plurality of channels, wherein each channel in the plurality of channels comprises a single opening at a first end of the channel and a closed end opposite the opening, wherein the opening of each channel in the plurality of channels is pointed in a different direction from the opening of each other channel in the plurality of channels, and a plurality of sensor devices comprising a sensor device at the closed end of each channel in the plurality of channels, wherein each sensor device in the plurality of sensor devices is configured to generate a sensor signal in response to pressure; 
 processing the sensor signals generated by the plurality of sensor devices using an algorithm to determine the direction of the infrasound received by the directional infrasound sensor; 
 receiving other infrasound from a known direction by the directional infrasound sensor; and 
 processing the sensor signals generated by the plurality of sensor devices in response to receiving the other infrasound by the directional infrasound sensor to calibrate the algorithm. 
 
     
     
       13. The method of  claim 12 , wherein air in the plurality of channels resonates in response to the infrasound received by the directional infrasound sensor. 
     
     
       14. The method of  claim 13 , wherein a shape of each channel in the plurality of channels is a fractal. 
     
     
       15. The method of  claim 12 , wherein a shape of each channel in the plurality of channels is a fractal. 
     
     
       16. The method of  claim 12 , wherein a shape of each channel in the plurality of channels along a length of the channel between the opening and the closed end of the channel is selected from straight and a coil shape. 
     
     
       17. The method of  claim 12 , wherein a length of each channel in the plurality of channels between the opening and the closed end of the channel is different from the length of each other channel in the plurality of channels. 
     
     
       18. The method of  claim 12 , wherein:
 a first opening of a first channel in the plurality of channels points in a first direction; 
 a second opening of a second channel in the plurality of channels points in a second direction, wherein the second direction is opposite to the first direction; 
 a third opening of a third channel in the plurality of channels points in a third direction, wherein the third direction is perpendicular to the first direction and to the second direction; and 
 a fourth opening of a fourth channel in the plurality of channels points in a fourth direction, wherein the fourth direction is opposite to the third direction. 
 
     
     
       19. The method of  claim 12 , wherein each channel in the plurality of channels is defined by walls made from a material selected from a group of materials consisting of concrete and metal. 
     
     
       20. The method of  claim 12 , wherein each sensor device in the plurality of sensor devices comprises a pressure sensor.